Power Conversion Apparatus

ABSTRACT

An object of the present invention is to improve the cooling performance of a capacitor module used in a power conversion apparatus. The power conversion apparatus according to the present invention includes a power semiconductor module, a capacitor module, a flow path forming body that forms a flow path through which a cooling refrigerant flows . The flow path forming body includes a first flow path forming body that forms a first flow path part for cooling the power semiconductor module, and a second flow path forming body that forms a second flow path part for cooling the capacitor module. The first flow path forming body is provided on a side portion of the second follow path forming body and is integrally formed with the second flow path forming body. The second flow path forming body forms a housing space for housing the capacitor module above the second flow path part . The first flow path part is formed at a position facing the side wall that forms the housing space. The power semiconductor module is inserted into the first flow path part.

TECHNICAL FIELD

The present invention relates to a power conversion apparatus used toconvert DC power to AC power or to convert AC power to DC power, andmore particularly to a power conversion apparatus used for hybridelectric vehicles and electric vehicles.

BACKGROUND ART

In general, a power conversion apparatus includes a smoothing capacitormodule for receiving DC power from a DC power supply, an invertercircuit for receiving the DC power from the capacitor module to generateAC power, and a control circuit for controlling the inverter circuit. Inrecent years, it has been required for high output in a power conversionapparatus. In particular, in the field of hybrid electric vehicles andelectric vehicles, the operating time using a motor as a drive source,as well as the operating conditions (high output torque conditions) tendto increase. Thus, the DC power supplied from the DC power supply to thepower conversion apparatus tends to increase as well. The greater the DCpower supplied from the DC power supply, the greater the heat generatedin a capacitor cell and a bus bar that are provided in the capacitormodule.

Japanese Unexamined Patent Application Publication No. 2009-219270discloses an example of a power conversion apparatus in which a flowpath is formed to surround a capacitor module, in order to improve thecooling performance of the capacitor module.

However, there is a demand for further improvement of the coolingperformance of the capacitor module.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application PublicationNo. 2009-219270

SUMMARY OF INVENTION 1. Technical Problem

An object of the present invention is to improve the cooling performanceof a capacitor module used in a power conversion apparatus.

2. Solution to Problem

In order to solve the above problem, a power conversion apparatusaccording to the present invention includes a flow path forming body forcooling a power semiconductor module and a capacitor module. The flowpath forming body forms a housing space for housing the capacitor moduleabove a second flow path part to cool the capacitor module. Then, afirst flow path part is formed at a position facing the side wall thatforms the housing space.

Because of this structure, the capacitor module is cooled by the bottomand side surfaces of the capacitor module, so that the coolingperformance of the capacitor module is improved.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to improve thecooling performance of the capacitor module.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a system diagram showing a system of a hybrid electricvehicle.

FIG. 2 is a circuit diagram showing the structure of the electricalcircuit shown in FIG. 1.

FIG. 3 is an exploded perspective view showing the structure of a powerconversion apparatus.

FIG. 4 is a perspective view of the power conversion apparatusdisassembled into components to show the overall structure.

FIG. 5 is a view seen from the bottom side of the flow path forming body12 shown in FIG. 4 to show the flow path forming body 12.

FIG. 6( a) is a perspective view showing the external appearance of apower semiconductor module 300 a, and FIG. 6 (b) is a cross-sectionalview of the power semiconductor module 300 a.

FIG. 7( a) is a perspective view, 7(b) is a cross-sectional view similarto FIG. 6( b) taken along the cross section D as viewed from thedirection E, and FIG. 7( c) is a cross-sectional view of a thin wallportion 304A before deformed due to a pressure applied to a fin 305.

FIGS. 8 are views of the power semiconductor module 300 a with a modulecase 304 further removed from the state shown in FIG. 7, in which FIG.8( a) is a perspective view, and FIG. 8 (b) is a cross-sectional viewsimilar to FIG. 7( b) taken along the cross section D as viewed from thedirection E.

FIG. 9 is a perspective view of the power semiconductor module 300 awith a first sealing resin 348 and a wiring insulating portion 608 beingfurther removed from the state shown in FIG. 8.

FIG. 10 is a view for illustrating the assembly process of a moduleprimary sealant 302.

FIG. 11 (a) is a perspective view showing the external appearance of acapacitor module 500, and FIG. 11( b) is an exploded perspective viewshowing the internal structure of the capacitor module 500.

FIG. 12 is a cross-sectional view of a power conversion apparatus 200taken along the A-A plane in FIG. 3.

FIG. 13 is an exploded perspective view of a driver circuit board 22 anda metal base plate 11 with a lid 8 and a control circuit board 20removed.

FIG. 14 is a cross-sectional perspective view taken along the planes Bin FIG. 13.

FIG. 15 is a cross-sectional view taken along the plane C of the flowpath forming body 12 shown in FIG. 5.

FIG. 16 is a top surface view of the power conversion apparatus 200 withthe lid 8, the control circuit board 20, the metal base plate 11, andthe driver circuit board 22 being removed.

DESCRIPTION OF EMBODIMENTS

Next, an embodiment of the present invention will be described withreference to the accompanying drawings. FIG. 1 is a system diagram inwhich a power conversion apparatus according to the present invention isapplied to the so-called hybrid electric vehicle that runs by both anengine and a motor. The power conversion apparatus according to thepresent invention can be applied not only to the hybrid electric vehiclebut also the so-called electric vehicle that runs only by a motor.Further, the power conversion apparatus can also be used as a powerconversion apparatus for driving motors used in general industrialmachinery. However, as described above or below, in particular when thepower conversion apparatus according to the present invention is appliedto the hybrid electric vehicle and the electric vehicle, an excellenteffect can be obtained in terms of various aspects such as downsizingand reliability. The power conversion apparatus applied to the hybridelectric vehicle has substantially the same structure as that of thepower conversion apparatus applied to the electric vehicle. Thus, thepower conversion apparatus applied to the hybrid electric vehicle willbe described as a typical example.

FIG. 1 is a view of a control block of a hybrid electric vehicle(hereinafter referred to as “HEV”) . An engine EGN, a motor generatorMG1, and a motor generator MG2 produce a torque for running the vehicle. Further, the motor generator MG1 and the motor generator MG2 have afunction of not only producing a rotational torque but also convertingthe mechanical energy, which is added to the motor generator MG1 or themotor generator MG2 from the outside, into electrical power. The motorgenerator MG1 or MG2 is, for example, a synchronous machine or aninduction machine. As described above, the motor generator MG1 or MG2also acts as a motor or a power generator depending on the operationmethod.

The torque on the output side of the engine EGN and the output torque ofthe motor generator MG2 are transferred to the motor generator MG1through a power transfer mechanism TSM. The rotational torque from thepower transfer mechanism TSM, or the rotational torque produced by themotor generator MG1 is transferred to wheels through a transmission TMand a deferential gear DEF. On the other hand, in regenerative brakingoperation, the rotational torque is transferred from the wheels to themotor generator MG1. Then, the motor generator MG1 generates AC powerbased on the supplied rotational torque. The generated AC power isconverted to DC power by the power conversion apparatus 200 as describedbelow, to charge a high voltage battery 136. Then, the charged power isused as a traveling energy again. Further, when the power charged in thehigh voltage battery 136 runs low, it is possible to charge the battery136 by converting the rotation energy generated by the engine EGN intoAC power by the motor generator MG2, and by converting the AC power intoDC power by the power conversion apparatus 200. The transfer of themechanical energy from the engine EGN to the motor generator MG2 isperformed by the power transfer mechanism TSM.

Next, the power conversion apparatus 200 will be described. An invertercircuit 140 and an inverter circuit 142 are electrically coupled throughthe battery 136 and a DC connector 138. The power is mutuallytransferred between the battery 136 and the inverter circuit 140 or 142.When the motor generator MG1 is operated as a motor, the invertercircuit 140 generates AC power based on the DC power supplied from thebattery 136 through the DC connector 138. Then, the inverter circuit 140supplies the AC power to the motor generator MG1 through an AC connector188. The structure of the motor generator MG1 and the inverter circuit140 acts as a first motor generator unit. Similarly, when the motorgenerator MG2 is operated as a motor, the inverter circuit 142 generatesAC power based on the DC power supplied from the battery 136 through theDC connector 138. Then, the inverter circuit 142 supplies the AC powerto the motor generator MG2 through an AC terminal 159. The structure ofthe motor generator MG2 and the inverter circuit 142 acts as a secondmotor generator unit. Both the first motor generator unit and the secondmotor generator unit are operated as motors or generators, or they areoperated differently depending on the operation state. Further, it isalso possible that one of the first and second motor generator units isnot operated and is stopped.

Note that in the present embodiment, it is possible to drive the vehicleonly by the power of the motor generator MG1 by allowing the first motorgenerator unit to operate as an electrical operation unit by the powerof the battery 136. Further, in the present embodiment, the first motorgenerator unit or the second motor generator unit is allowed to act as apower generation unit by the power of the engine EGN or the power fromthe wheels, to generate power and thus the battery 136 can be charged.

The battery 136 is also used as a power supply for driving an auxiliarymotor 195. Examples of the auxiliary motor are a motor for driving acompressor of an air conditioner, or a motor for driving a hydraulicpump for cooling. The DC power is supplied from the battery 136 to anauxiliary power module 350. Then, AC power is generated by the auxiliarypower module 350 and is supplied to the auxiliary motor 195 through anAC terminal 120. Basically, the auxiliary power module 350 has the samecircuit structure and function as the inverter circuits 140 and 142. Theauxiliary power module 350 controls the phase, frequency, and power ofthe alternating current to be supplied to the auxiliary motor 195. Thecapacity of the auxiliary motor 195 is smaller than the capacity of themotor generators MG1 and MG2, so that the maximum conversion power ofthe auxiliary power module 350 is smaller than that of the respectiveinverter circuits 140 and 142. However, the basic structure of theauxiliary power module 350 and the basic operation thereof aresubstantially the same as those of the inverter circuits 140 and 142 asdescribed above. Note that the power conversion apparatus 200 includes acapacitor module 500 for smoothing the DC power to be supplied to theinverter circuit 140, the inverter circuit 142, and an inverter circuit350B.

The power conversion apparatus 200 includes a communication connector 21for receiving an instruction from the upper control device, or fortransmitting data showing the state to the upper control device. Basedon the instruction from the connector 21, the power conversion apparatus200 calculates the amount of control of the motor generator MG1, themotor generator MG2, and the auxiliary motor 195. Further, the powerconversion apparatus 200 calculates whether to operate as a motor or agenerator. Then, the power conversion apparatus 200 generates a controlpulse based on the calculation result, and supplies the control pulse toa driver circuit 174 as well as a driver circuit 350A of the auxiliarypower module 350. The auxiliary power module 350 may have a dedicatedcontrol circuit. In this case, the dedicated control circuit generates acontrol pulse based on the instruction from the connector 21, andsupplies the control pulse to the driver circuit 350A of the auxiliarypower module 350.

Based on the control pulse, the driver circuit 174 generates a drivepulse for controlling the inverter circuit 140 and the inverter circuit142. Further, the diver circuit 350A generates a control pulse fordriving the inverter circuit 350B of the auxiliary power module 350.

Next, the structure of the electric circuit of the inverter circuit 140and the inverter circuit 142 will be described with reference to FIG. 2.Also the circuit structure of the inverter circuit 350B of the auxiliarypower module 350 shown in FIG. 1 is basically similar to the circuitstructure of the inverter circuit 140. Thus, the detailed description ofthe circuit structure of the inverter circuit 350B is omitted in FIG. 2,and the inverter circuit 140 will be described as a typical example.However, the output power of the auxiliary power module 350 is small, sothat a semiconductor chip that forms upper and lower arms of each phasedescribed below, as well as a circuit connecting the particular chip areaggregated and placed in the auxiliary power module 350.

Further, the circuit structures and operations of the inverter circuit140 and the inverter circuit 142 are very similar to each other. Thus,the inverter circuit 140 will be described as representative.

Note that an insulating gate bipolar transistor is used below as asemiconductor element, which is hereafter referred to as IGBT. Theinverter circuit 140 includes an upper and lower arm series circuit 150having an IGBT 328 and diode 156 acting as an upper arm, and an IGBT 330and diode 166 acting as a lower arm. The upper and lower arm seriescircuit 150 is provided corresponding to each of the three phases, Uphase, V phase, and W phase of the AC power to be output.

In the present embodiment, the three phases correspond to the respectivephase windings of three phases of the armature winding of the motorgenerator MG1. In each of the upper and lower arm series circuits 150 ofthe three phases, AC current is output from an intermediate electrode168 which is a midpoint part of the series circuit. The AC current iscoupled to an AC bus bar 802 which is an AC power line to the motorgenerator MG1 as described below, through the AC terminal 159 or the ACconnector 188.

A collector electrode 153 of the IGBT 328 of the upper arm iselectrically coupled to a capacitor terminal 506 on the positiveelectrode side of the capacitor module 500 through a positive electrodeterminal 157. Then, an emitter electrode of the IGBT 330 of the lowerarm is electrically coupled to a capacitor terminal 504 on the negativeelectrode side of the capacitor module 500 through a negative electrodeterminal 158.

The IGBT 328 includes the collector electrode 153, a signal emitterelectrode 155, and a gate electrode 154. Further, the IGBT 330 includesa collector electrode 163, a signal emitter electrode 165, and a gateelectrode 164. The diode 156 is electrically coupled between thecollector electrode 153 and the emitter electrode. Further, the diode166 is electrically coupled between the collector electrode 163 and theemitter electrode. A metal-oxide-semiconductor field-effect transistor(hereinafter referred to as MOSFET) maybe used as a switching powersemiconductor element. In this case, the diode 156 and the diode 166 maynot be necessary. As the switching power semiconductor element, IGBT issuitable for the case where the DC voltage is relatively high, andMOSFET is suitable for the case where the DC voltage is relatively low.

The capacitor module 500 includes multiple capacitor terminals 506 onthe positive electrode side, multiple capacitor terminals 504 on thenegative electrode side, a battery positive terminal 509, and a batterynegative terminal 508. A high-voltage DC power from the battery 136 issupplied to the battery positive terminal 509 and the battery negativeterminal 508 through the DC connector 138. Then, the high-voltage DCpower is supplied from the multiple capacitor terminals 506 on thepositive electrode side of the capacitor module 500 and multiplecapacitor terminals 504 on the negative electrode side of the capacitormodule 500, to the inverter circuit 140, the inverter circuit 142, andthe auxiliary power module 350. On the other hand, the DC power that isconverted from the AC power by the inverter circuit 140 and the invertercircuit 142 is supplied to the capacitor module 500 from the capacitorterminal 506 on the positive electrode side and the capacitor terminal504 on the negative electrode side. Then, the DC power is supplied tothe battery 136 from the battery positive terminal 509 and the batterynegative terminal 508 through the DC connector 138, and is accumulatedin the battery 136.

A control circuit 172 includes a microcomputer (hereinafter referred toas “Micon”) for performing arithmetic processing of the switching timingof the IGBT 328 and the IGBT 330. The information input to the Miconincludes the target torque value required for the motor generator MG1,the current value supplied from the upper and lower arm series circuit150 to the motor generator MG1, and the magnetic pole position of therotor of the motor generator MG1. The target torque value is based on aninstruction signal output from the upper control device not shown. Thecurrent value is detected based on a detection signal from a currentsensor 180. The magnetic pole position is detected based on a detectionsignal output from a rotary magnetic pole sensor (not shown) such as aresolver provided in the motor generator MG1. In the present embodiment,it is assumed that the current sensor 180 detects current values ofthree phases. However, it is also possible to detect the current valuesof two phases and obtain the current of three phases by calculation.

FIG. 3 is an exploded perspective view of the power conversion apparatus200 as an embodiment according to the present invention. The powerconversion apparatus 200 includes a flow path forming body 12 thatfunctions as a case for housing power semiconductor modules 300 a to 300c and power semiconductor modules 301 a to 301 c described below, aswell as the capacitor module 500. Further, the power conversionapparatus 200 also includes the lid 8. Note that it is also possible tohave a structure in which a case body is provided separately from theflow path forming body 12 of the present embodiment, and the flow pathforming body 12 is housed in the case.

The lid 8 houses the circuit component of the power conversion apparatus200 and is fixed to the flow path forming body 12 . The control circuitboard 20 on which the control circuit 172 is mounted is placed in theinner upper portion of the lid 8. A first opening 202, a third opening204 a, a fourth opening 204 b, and a fifth opening 205 are provided onthe upper surface of the lid 8. Further, a second opening 203 isprovided on the side wall of the lid 8.

The connector 21 is provided in the control circuit board 20, protrudingto the outside through the first opening 202. The negative side powerline 510 and the positive side power line 512 electrically couple the DCconnector 138 to the capacitor module 500 and the like, and protrude tothe outside through the second opening 203.

AC-side relay conductors 802 a to 802 c are connected to the powersemiconductor modules 300 a to 300 c, respectively, and protrude to theoutside through the third opening 204 a. AC-side relay conductors 802 dto 802 f are connected to the power semiconductor modules 301 a to 301c, respectively, and protrude to the outside through the fourth opening204 b. The AC output terminal of the auxiliary power module 350, notshown, protrudes to the outside through the fifth opening 205.

The direction of the fitting surface of the terminal of the connector21, and the like, varies depending on the type of vehicle. Inparticular, when it is desired to mount on a small vehicle, it ispreferable to allow the terminal to protrude outwardly with the fittingsurface upward, in terms of the limitations in size of the engine roomas well as the ease of assembly. For example, when the power conversionapparatus 200 is provided above the transmission TM, the workability isimproved by allowing the terminal to protrude to the side opposite tothe side on which the transmission TM is provided.

FIG. 4 is an overall exploded perspective view that helps to understandthe structure housed in the flow path forming body 12 of the powerconversion apparatus 200.

The flow path forming body 12 forms opening parts 400 a to 400 c andopening parts 402 a to 402 c that lead to the flow path through which acooling refrigerant flows. The opening parts 400 a to 400 c are filledwith the inserted power semiconductor modules 300 a to 300 c. Further,openings 402 d to 402 f are filled with the inserted power semiconductormodules 301 a to 301 c.

In the flow path forming body 12, a housing space 405 for housing thecapacitor module 500 is formed on the side of the space in which thepower semiconductor modules 300 a to 300 c and the power semiconductormodules 301 a to 301 c are housed.

The capacitor module 500 has a substantially constant distance from thepower semiconductor modules 300 a to 300 c and from the powersemiconductor modules 301 a to 301 c, so that the circuit constant caneasily be balanced between the smoothing capacitor and the powersemiconductor module circuit in each of the three phases. Thus, it ispossible to achieve a circuit structure in which the spike voltage caneasily be reduced.

By integrally forming the main structure of the flow path of the flowpath forming body 12 with the flow path forming body 12 by casting analuminum material, it is possible to increase the mechanical strength ofthe flow path, in addition to obtaining the cooling effect. Further, theflow path forming body 12 and the flow path are formed into an integralstructure by aluminum casting, so that the heat transfer is increasedand the cooling efficiency is improved. Note that the powersemiconductor modules 300 a to 300 c and the power semiconductor modules301 a to 301 c are fixed to the flow path to complete the flow path.Then, a water leakage test is performed on the water path. Once thewater path passes the water leakage test, it is allowed to perform theoperation of mounting the capacitor module 500, the auxiliary powermodule 350, and the substrate. As described above, the flow path formingbody 12 is provided on the bottom of the power conversion apparatus 200,and then the necessary components such as the capacitor module 500, theauxiliary power module 350, and the substrate are fixed sequentiallyfrom the top. Thus, the productivity and reliability are increased.

The driver circuit board 22 is provided above the power semiconductormodules 300 a to 300 c, the power semiconductor modules 301 a to 301 c,and the capacitor module 500. Further, the metal base plate 11 isprovided between the driver circuit board 22 and the control circuitboard 20. The metal base plate 11 has the function of theelectromagnetic shield of the circuit group mounted on the drivercircuit board 22 and the control circuit board 20, and at the same timehas the capacity to release heat generated by the driver circuit board22 and the control circuit board 20 to cool down.

Further, the metal base plate 11 acts to increase the mechanicalresonant frequency of the control circuit board 20. In other words, thescrew parts for fixing the control circuit board 20 to the metal base 11can be provided at short intervals. As a result, the distance betweenthe supporting points can be reduced when mechanical vibration occurs,so that the resonant frequency can be increased. For example, theresonant frequency of the control circuit board 20 can be increased withrespect to the vibration frequency transferred from the transmission, sothat the control circuit board 20 is unlikely to be affected by thevibration and the reliability is increased.

FIG. 5 is a view for illustrating the flow path forming body 12, whichis seen from the bottom of the flow path forming body 12 shown in FIG.4.

In the flow path forming body 12, an inlet pipe 13 and an outlet pipe 14are provided on one side wall 12 a. The cooling refrigerant flows in thedirection of a flow direction 417 indicated by the dotted line, andflows to a first flow path part 19 a formed along one side of the flowpath forming body 12, through the inlet pipe 13. A second flow path part19 b is connected to the first flow path portion 19 a through a returnflow path part, and is formed parallel to the first flow path part 19 a.A third flow path part 19 c is connected to the second flow path part 19b through a return flow path part, and is formed parallel to the secondflow path part 19 b. A fourth flow path part 19 d is connected to thethird flow path part 19 c through a return flow path part, and is formedparallel to the third flow path part 19 c. A fifth flow path part 19 eis connected to the fourth flow path part 19 d through a return flowpath part, and is formed parallel to the fourth flow path part 19 d. Asixth flow path part 19 f is connected to the fifth flow path part 19 ethrough a return flow path part, and is formed parallel to the fifthflow path part 19 e. In other words, the first to sixth flow path parts19 e to 19 f are connected to form a meander flow path.

A first flow path forming body 441 forms the first flow path part 19 a,the second flow path part 19 b, the third flow path part 19 c, thefourth flow path part 19 d, the fifth flow path part 19 e, and the sixthflow path part 19 f. The first flow path part 19 a, the second flow pathpart 19 b, the third flow path part 19 c, the fourth flow path part 19d, the fifth flow path part 19 e, and the sixth flow path part 19 f areformed larger in the depth direction than in the width direction,respectively.

The seventh flow path part 19 g leads to the sixth flow path part 19 f,and is formed at a position facing the housing space 405 of thecapacitor module 500 shown in FIG. 4. A second flow path forming body442 forms the seventh flow path part 19 g. The seventh flow path part 19g is formed larger in the width direction than in the depth direction.

An eighth flow path part 19 h leads to the seventh flow path part 19 g,and is formed at a position facing the auxiliary power module 350described below. Further, the eighth flow path part 19 h is connected tothe outlet pipe 14. A third flow path forming body 444 forms the eighthflow path part 19 h. The eighth flow path part 19 h is formed larger inthe depth direction than in the width direction.

An opening portion 404 to which all the flow path parts lead asdescribed above is formed on the lower surface of the flow path formingbody 12. The opening portion 404 is closed by a lower cover 420. A sealmember 409 is provided between the lower cover 420 and the flow pathforming body 12 to keep air tightness.

Further, protruding portions 406 a to 406 f protruding to the directionaway from the flow path forming body 12 are formed in the lower cover420. The protruding portions 406 a to 406 f are provided correspondingto the power semiconductor modules 300 a to 300 c and the powersemiconductor modules 301 a to 301 c. In other words, the protrudingportion 406 a is formed facing the first flow path part 19 a. Theprotruding portion 406 b is formed facing the second flow path part 19b. The protruding portion 406 c is formed facing the third flow pathpart 19 c. The protruding portion 406 d is formed facing the forth flowpath part 19 d. The protruding portion 406 e is formed facing the fifthflow path part 19 e. The protruding portion 406 f is formed facing thesixth flow path part 19 f.

The depth and width of the seventh flow path part 19 g greatly vary fromthe depth and width of the sixth flow path part 19 f. In order to beable to rectify the flow of the cooling refrigerant and to manage theflow rate in the significant change in the shape of the flow path, it isdesirable that the second flow path forming body 442 is provided with astraight fin 447 protruding to the seventh flow path part 19 g.

Similarly, the depth and width of the eighth flow path part 19 h greatlyvary from the depth and width of the seventh flow path part 19 g. Inorder to be able to rectify the flow of the cooling refrigerant and tomanage the flow rate in the significant change in the shape of the flowpath, it is desirable that the third flow path forming body 444 isprovided with a straight fin 448 protruding to the eighth flow path part19 h.

The detailed structure of the power semiconductor modules 300 a to 300 cused in the inverter circuit 140 will be described with reference toFIGS. 6 to 10. The power semiconductor modules 300 a to 300 c have thesame structure, so that the structure of the power semiconductor module300 a will be described as representative. Note that in FIGS. 6 to 10, asignal terminal 325U corresponds to the gate electrode 154 and signalemitter electrode 155 disclosed in FIG. 2, and a signal terminal 325Lcorresponds to the gate electrode 164 and emitter electrode 165disclosed in FIG. 2. Further, a DC positive electrode terminal 315B isthe same as the positive electrode terminal 157 disclosed in FIG. 2, anda DC negative electrode terminal 319B is the same as the negativeelectrode terminal 158 disclosed in FIG. 2. Further, an AC terminal 320Bis the same as the AC terminal 159 disclosed in FIG. 2.

FIG. 6( a) is a perspective view of the power semiconductor module 300 aof the present embodiment. FIG. 6( b) is a cross-sectional view takenalong the cross section D of the power semiconductor module 300 a of thepresent embodiment, as viewed from the direction E.

FIG. 7 is a view showing the power semiconductor module 300 a, in whicha screw 309 and a second sealing resin 351 are removed from the stateshown in FIG. 6 to help understanding. FIG. 7( a) is a perspective view,and FIG. 7( b) is a cross-sectional view similar to FIG. 6( b) takenalong the cross section D as viewed from the direction E. Further, FIG.7( c) is a cross-sectional view of a thin wall portion 304A beforedeformed due to a pressure applied to the fin 305.

FIG. 8 is a view of the power semiconductor module 300 a, in which themodule case 304 is further removed from the state shown in FIG. 7. FIG.8( a) is a perspective view, and FIG. 8( b) is a cross-sectional viewsimilar to FIGS. 6( b) and 7(b) taken along the cross section D asviewed from the direction E.

FIG. 9 is a perspective view of the power semiconductor module 300 a, inwhich the first sealing resin 348 and the wiring insulating portion 608are further removed from the state shown in FIG. 8.

FIG. 10 is a view for illustrating the assembly process of the moduleprimary sealant 302. The power semiconductor elements (the IGBT 328,IGBT 330, diode 156, and diode 166) forming the upper and lower armseries circuit 150 are fixed so as to be sandwiched between a conductorplate 315 and a conductor plate 318 or between a conductor plate 320 anda conductor plate 319 as shown in FIGS. 8 and 9. The conductor plate 315and the like are sealed by the first sealing resin 348 with theradiating surface being exposed, and an insulation member 333 isthermally compressed to the radiating surface. The first sealing resin348 has a polyhedron shape (substantially rectangular parallelepipedshape in this case) as shown in FIG. 8.

The module primary sealant 302 sealed by the first sealing resin 348 isinserted into the module case 304, and is thermally compressed to theinner surface of the module case 304, which is a CAN-type cooler, withthe insulation member 333 therebetween. Here, the CAN-type cooler is acooler of a cylindrical shape with an insertion opening 306 on onesurface and with a bottom on the other side. A void remaining in theinterior of the module case 304 is filled with the second sealing resin351.

The module case 304 is formed of a member having an electricalconductivity, for example, an aluminum alloy material (Al, AlSi, AlSiC,Al—C, and the like). The outer periphery of the insertion opening 306 issurrounded by a flange 304B. Further, as shown in FIG. 6( a), a firstradiating surface 307A and a second radiating surface 307B, each havingan area greater than that of the other surfaces, are provided facingeach other. Then, the respective power semiconductor elements (IGBT 328,IGBT 330, diode 156, and diode 166) are arranged so as to face therespective radiating surfaces.

The three surfaces connecting to the opposing first and second radiatingsurfaces 307A and 307B form a plane that is sealed at a width smallerthan the first and second radiating surfaces 307A and 307B. Then, theinsertion opening 306 is formed on the plane of the one remaining side.The module case 304 does not necessarily have an exact rectangularshape, and may have rounded corners as shown FIG. 6( a).

By using the case of metal having such a shape, it is possible to ensurethe seal for the refrigerant in the flange 304B, even if the module case304 is inserted into the flow path through which the refrigerant such aswater or oil flows. Thus, it is possible to prevent the coolingrefrigerant from entering the interior of the module case 304 by asimple structure. Further, the fins 305 are uniformly formed in theopposing first and second radiating surfaces 307A and 307B,respectively. Further, the thin wall portion 304A whose thickness isextremely thin is formed in the outer periphery of the first radiatingsurface 307A and the second radiating surface 307B. The thickness of thethin wall portion 304A is significantly reduced to the extent that it iseasily deformed due to a pressure applied to the fin 305, so that theproductivity after the insertion of the module primary sealant 302 isincreased.

As described above, by thermally compressing the conductor plate 315 andthe like to the inner wall of the module case 304 through the insulationmember 333, it is possible to reduce the void between the conductorplate 315 and the like, and the inner wall of the module case 304. Thus,the heat generated by the power semiconductor element can be transferredto the fin 305 effectively. Further, by allowing the insulation member333 to have a certain thickness and flexibility, it is possible toabsorb the generation of thermal stress by the insulation member 333,which is better to be used in the power conversion apparatus for thevehicle in which the temperature change is significant.

A DC positive electrode wiring 315A and a DC negative electrode wiring319A, which are formed of metal, are provided on the outside of themodule case 304 to electrically couple to the capacitor module 500. A DCpositive electrode terminal 315B and a DC negative electrode terminal319B are formed at the tip portion of the DC positive electrode 315A andat the tip portion of the DC negative electrode wiring 319A,respectively. Further, an AC wiring 320A of metal is provided to supplyAC power to the motor generator MG1 or MG2. Then, an AC terminal 320B isformed at the tip portion of the AC electrode wiring 320A. In thepresent embodiment, as shown in FIG. 9, the DC positive electrode wiring315A is connected to the conductor plate 315, the DC negative electrodewiring 319A is connected to the conductor plate 319, and the AC wiring320A is connected to the conductor plate 320.

Signal wirings 324U and 324L of metal are also provided on the outsideof the module case 304 to electrically couple to the driver circuit 174.Then, a signal terminal 325U and a signal terminal 325L are formed atthe tip portion of the signal wiring 324U and at the tip portion of thesignal wiring 324L, respectively. In the present embodiment, as shown inFIG. 9, the signal wiring 324U is connected to the IGBT 328 and thesignal wiring 324L is connected to the IGBT 330.

The DC positive electrode wiring 315A, the DC negative electrode wiring319A, the AC wiring 320A, the signal wiring 324U, and the signal wiring324L are integrally formed as an auxiliary mold body 600, in such a waythat they are insulated from each other by the wiring insulating portion608 formed by a resin material. The wiring insulating portion 608 alsoacts as a support member for supporting each wiring. A thermosetting orthermoplastic resin with insulation properties is suitable for the resinmaterial used for the wiring insulating portion 608. In this way, it ispossible to ensure insulation between each of the DC positive electrodewiring 315A, the DC negative electrode wiring 319A, the AC wiring 320A,the signal wiring 324U, and the signal wiring 324L. As a result, highdensity wiring can be achieved.

The auxiliary module body 600 is bonded with a metal in the moduleprimary sealant 302 and a connection part 370. Then, the auxiliarymodule body 600 is fixed to the module case 304 by the screw 309 passingthrough a screw hole provided in the wiring insulating portion 608. Forexample, TIG welding can be used in the metal bonding of the moduleprimary sealant 302 and the auxiliary mold body 600 in the connectionpart 370.

The DC positive electrode wiring 315A and the DC negative electrodewiring 319A are laminated face to face with the wiring insulatingportion 608 interposed therebetween, and are of a shape extendingsubstantially parallel to each other. Because of the arrangement andshape described above, the current that instantaneously flows in theswitching operation of the power semiconductor element is oppositelyoriented and flows in the opposite direction. In this way, the magneticfields generated by the current act to cancel each other out, so thatlow inductance can be achieved by this action. Note that the AC wiring320A and the signal terminals 325U and 325L also extend in the samedirection as the direction of the DC positive electrode wiring 315A andthe DC negative electrode wiring 319A.

The connection part 370 in which the module primary sealant 302 and theauxiliary mold body 600 are bonded with a metal is sealed within themodule case 304 by the second sealing resin 351. In this way, it ispossible to stably ensure the required insulation distance between theconnection part 370 and the module case 304. Thus, the reduction in sizeof the power semiconductor module 300 a can be achieved as compared tothe case where the connection part 370 is not sealed.

As shown in FIG. 9, an auxiliary module-side DC positive electrodeconnection terminal 315C, an auxiliary module-side DC negative electrodeconnection terminal 319C, an auxiliary module-side AC connectionterminal 320C, an auxiliary module-side signal connection terminal 326U,and an auxiliary module-side signal connection terminal 326L arearranged in a line in the connection part 370 on the side of theauxiliary mold body 600. On the other hand, an element-side DC positiveelectrode connection terminal 315D, an element-side DC negativeelectrode connection terminal 319D, an element-side AC connectionterminal 320D, an element-side signal connection terminal 327U, and anelement-side signal connection terminal 327L are arranged in a linealong one surface of the first sealing resin 348 having a polyhedronshape, in the connection part 370 on the side of the module primarysealant 302. By configuring the connection part 370 in which therespective terminals are arranged in a line, it is easy to produce themodule primary sealant 302 by transfer molding.

Here, the positional relationship between the respective terminals willbe described, in which the portion extending outward from the firstsealing resin 348 of the module primary sealant 302 is viewed as aterminal for each type. In the following description, the terminalformed by the DC positive electrode wiring 315A (including the DCpositive electrode terminal 315B and the auxiliary module-side DCpositive electrode connection terminal 315C) and the element-side DCpositive electrode terminal 315D is referred to as the positiveterminal. Further, the terminal formed by the DC negative electrodewiring 319A (including the DC negative electrode terminal 319B and theauxiliary module-side DC negative electrode connection terminal 319C)and the element-side DC positive electrode connection terminal 315D isreferred to as the negative terminal. The terminal formed by the ACwiring 320A (including the AC terminal 320B and the auxiliarymodule-side AC connection terminal 320C) and the element-side ACconnection terminal 320D is referred to as the output terminal. Theterminal formed by the signal wiring 324U (including the signal terminal325U and the auxiliary module-side signal connection terminal 326U) andthe element-side signal connection terminal 327U is referred to as theupper arm signal terminal. Then, the terminal formed by the signalwiring 324L (including the signal terminal 325L and the auxiliarymodule-side signal connection terminal 326L) and the element-side signalconnection terminal 327L is referred to as the lower arm signalterminal.

Each of the terminals protrudes from the first sealing resin 348 and thesecond sealing resin 351 through the connection part 370. The protrudingportions protruding from the first sealing resin 348 (the element-sideDC positive electrode connecting terminal 315D, the element-side DCnegative electrode connection terminal 319D, the element-side ACconnection terminal 320D, the element-side signal connection terminal327U, and the element-side signal connection terminal 327L) are arrangedin a line along one surface of the first sealing resin 348 having apolyhedron shape as described above. Further, the positive terminal andthe negative terminal protrude from the second sealing resin 351 in alaminated state, extending to the outside of the module case 304.Because of this structure, it is possible to prevent excessive stress onthe connection part of the power semiconductor element and theparticular terminal, and to prevent the gap from being generated in themold, at the time of mold clamping for producing the module primarysealant 302 by sealing the power semiconductor element by the firstsealing resin 348. Further, the opposing currents flowing through eachof the laminated positive and negative terminals generate magneticfluxes in the opposite directions to cancel each other out. As a result,low inductance can be achieved.

On the side of the auxiliary module body 600, the auxiliary module-sideDC positive electrode connection terminal 315C and the auxiliarymodule-side DC negative electrode connection terminal 319C are formed atthe tip portions of the DC positive electrode wiring 315A and the DCnegative electrode wiring 319A on the opposite side of the DC positiveelectrode terminal 315B and the DC negative electrode terminal 319B,respectively. Further, the auxiliary module-side AC connection terminal320C is formed at the tip portion of the AC wiring 320A on the oppositeside of the AC terminal 320B. The auxiliary module-side signalconnection terminals 326U, 326L are formed at the tip portions of thesignal wirings 324U, 324L on the opposite side of the signal terminals325U, 325L, respectively.

On the other hand, on the side of the module primary sealant 302, theelement-side DC positive electrode connection terminal 315D, theelement-side DC negative electrode connection terminal 319D, and theelement-side AC connection terminal 320D are respectively formed in theconductor plates 315, 319, and 320. Further, the element-side signalconnection terminals 327U, 327L are connected to the IGBTs 328, 330 by abonding wire 371, respectively.

As shown in FIG. 10, the DC positive side conductor plate 315 and the ACoutput side conductor plate 320, as well as the element-side signalconnection terminals 327U and 327L are connected to a common tie bar372, and are integrally formed so as to be substantially in the sameplane. A collector electrode of the IGBT 328 on the upper arm side and acathode electrode of the diode 156 on the upper arm side are fixed tothe conductor plate 315. A collector electrode of the IGBT 330 on thelower arm side and a cathode electrode of the diode 166 on the lower armside are fixed to the conductor plate 320. The conductor plate 318 andthe conductor plate 319 are arranged so as to be substantially in thesame plane, on the IGBTs 328, 330 and the diodes 156, 166. An emitterelectrode of the IGBT 328 on the upper arm side and an anode electrodeof the diode 156 on the upper arm side are fixed to the conductor plate318. An emitter electrode of the IGBT 330 on the lower arm side and ananode electrode of the diode 166 on the lower arm side are fixed to theconductor plate 319. Each of the power semiconductor elements is fixedto the element fixing part 322 provided in each conductor plate throughthe metal bonding material 160. Examples of the metal bonding material160 area solder material, silver sheet, and a low-temperature sinteringbonding material containing fine metal particles.

Each power semiconductor element has a flat plate-like structure, andthe respective electrodes of the power semiconductor element are formedon the front and back surfaces. As shown in FIG. 10, each of theelectrodes of the power semiconductor element is sandwiched between theconductor plate 315 and the conductor plate 318, or between theconductor plate 320 and the conductor plate 319. In other words, theconductor plate 315 and the conductor plate 318 are laminated face toface substantially in parallel to each other through the IGBT 328 andthe diode 156. Similarly, the conductor plate 320 and the conductorplate 319 are laminated face to face substantially in parallel to eachother through the IGBT 330 and the diode 166. Further, the conductorplate 320 and the conductor plate 318 are connected through anintermediate electrode 329. Because of this connection, the upper armcircuit and the lower arm circuit are electrically coupled to form theupper and lower arm series circuit. As described above, the IGBT 328 andthe diode 156 are sandwiched between the conductor plate 315 and theconductor plate 318. At the same time, the IGBT 330 and the diode 166are sandwiched between the conductor plate 320 and the conductor plate319 to connect the conductor plate 320 and the conductor plate 318through the intermediate electrode 329. Then, the control electrode 328Aof the IGBT 328 and the element-side signal connection terminal 327U areconnected by the bonding wire 371. At the same time, the controlelectrode 330A of the IGBT 330 and the element-side signal connectionterminal 327L are connected by the bonding wire 317.

FIG. 11( a) is a perspective view showing the external appearance of thecapacitor module 500. FIG. 11 (b) is an explode perspective view showingthe internal structure of the capacitor module 500. A laminatedconductor plate 501 is formed by a negative electrode conductor plate505 and a positive electrode conductor plate 507 that are formed by awide plate-like conductor, as well as an insulating sheet 550 sandwichedbetween the negative electrode conductor plate 505 and the positiveelectrode conductor 507. The laminated conductor plate 501 allows themagnetic fluxes to cancel each other out for the current flowing throughthe upper and lower arm series circuit 150 of each phase. Thus, lowinductance can be achieved with respect to the current flowing throughthe upper and lower arm series circuit 150.

The battery negative terminal 508 and the battery positive terminal 509are formed rising from one side in the longitudinal direction of thelaminated conductor plate 501. The battery negative terminal 508 and thebattery positive terminal 509 are connected to the positive electrodeconductor plate 507 and the negative electrode conductor plate 505,respectively. The auxiliary capacitor terminals 516 and 517 are formedrising from one side in the longitudinal direction of the laminatedconductor plate 501. The auxiliary capacitor terminals 516 and 517 areconnected to the positive electrode conductor plate 507 and the negativeelectrode conductor plate 505, respectively.

The relay conductor part 530 is formed rising from one side in thelongitudinal direction of the laminated conductor plate 501. Thecapacitor terminals 503 a to 503 c protrude from the tip portion of therelay conductor part 530. The capacitor terminals 503 a to 503 c areformed corresponding to the power semiconductor modules 300 a to 300 c,respectively. Further, capacitor terminals 503 d to 503 f also protrudefrom the tip portion of the relay conductor part 530. The capacitorterminals 503 d to 503 f are formed corresponding to the powersemiconductor modules 301 a to 301 c, respectively. All of the relayconductor part 530 and the capacitor terminals 503 a to 503 c areconfigured in a laminated structure with the insulating sheet 550interposed therebetween, in order to achieve low inductance of thecurrent flowing through the upper and lower arm series circuit 150.Further, the relay conductor part 530 is configured such that thethrough holes and the like that may prevent the current flow are notformed or reduced as much as possible.

Because of this structure, the return current, which is generated inswitching between the power semiconductor modules 300 a to 300 cprovided for each phase, can easily flow to the relay conductor part 530and is unlikely to flow to the side of the laminated conductor plate501. Thus, it is possible to reduce the heat generated in the laminatedconductor plate 501 due to the return current.

Note that in the present embodiment, the negative electrode conductorplate 505, the positive electrode conductor plate 507, the batterynegative terminal 508, the battery positive terminal 509, the relayconductor part 530, and the capacitor terminals 503 a to 503 f areconfigured by an integrally formed metal plate, and have the effect ofreducing the inductance of the current flowing through the upper andlower arm series circuit 150.

A plurality of the capacitor cells 514 are provided below the laminatedconductor plate 501. In the present embodiment, three capacitor cells514 are arranged in a line along one side in the longitudinal directionof the laminated conductor plate 501. Further, another three capacitorcells 514 are arranged in a line along the other side in thelongitudinal direction of the laminated conductor plate 501. Thus, sixcapacitor cells are provided in total.

The capacitor cells 514, which are arranged along the respective sidesin the longitudinal direction of the laminated conductor plate 501, aresymmetrically arranged with respect to the dotted line A-A shown in FIG.11( a). In this way, when the DC current smoothed by the capacitor cells514 is supplied to the power semiconductor modules 300 a to 300 c andthe power semiconductor modules 301 a to 301 c, the current balancebetween the capacitor terminals 503 a to 503 c and the capacitorterminals 503 d to 503 f is equalized, so that the inductance of thelaminated conductor plate 501 can be reduced. Further, it is possible toprevent the current from flowing locally in the laminated conductorplate 501. Thus, the thermal balance is equalized and the heatresistance can be improved.

The capacitor cell 514 is a unit structure of the power storage part ofthe capacitor module 500, using a film capacitor in which two films witha metal such as aluminum deposited on one surface are laminated andwound to form two metal layers as positive and negative electrodes,respectively. The electrodes of the capacitor cell 514 are produced byspraying a conductor such as tin, in which the wound axial surfacesserve as the positive and negative electrodes, respectively.

The capacitor case 502 includes a housing part 511 for housing thecapacitor cells 514. The housing part 511 has upper and lower surfaceseach having a substantially rectangular shape. The capacitor case 502includes holes 520 a to 520 d through which fixing means such as screwspass to fix the capacitor module 500 to the flow path forming body 12.The capacitor case 502 of the present invention is formed of resin withhigh thermal conductivity, but may be formed of metal or othermaterials.

Further, after the laminated conductor plate 501 and the capacitor cells514 are housed in the capacitor case 502, a filling material 551 isfilled in the capacitor case 502 so as to cover the laminated conductorplate 501, except the capacitor terminals 503 a to 503 f, the batterynegative terminal 508, and the battery positive terminal 509.

Further, capacitor cell 514 generates heat by the electric resistance ofthe metal thin film deposited on the inner film as well as the innerconductor, by the ripple current in switching. Thus, in order to make iteasy to release the heat of the capacitor cell 514 through the capacitorcase 502, the capacitor cell 514 is molded with the filling material.

In addition, by using the filling material of resin, it is possible toimprove the moisture resistance of the capacitor cell 514.

In the present embodiment, the seventh flow path part 19 g is providedalong the longitudinal direction of the housing part 511 of thecapacitor module 500 (see FIG. 5), so that the cooling efficiency isincreased.

Further, a noise filter capacitor cell 515 a is connected to thepositive electrode conductor plate 507 to remove a specific noisegenerated between the positive electrode and the ground. A noise filtercapacitor cell 515 b is connected to the negative electrode conductorplate 505 to remove a specific noise generated between the negativeelectrode and the ground. The capacity of the respective the noisefilter capacitor cells 515 a and 515 b is set smaller than the capacityof the capacitor cell 514. Further, the noise filter capacitor cells 515a and 515 b are placed closer to the battery negative terminal 508 andthe battery positive terminal 509 than the capacitor terminals 503 a to503 f are placed. In this way, it is possible to remove early a specificnoise that is mixed into the battery negative terminal 508 and thebattery positive-side terminal 509. As a result, it is possible toreduce the influence of the noise on the power semiconductor module.

FIG. 12 is a cross-sectional view of the power conversion apparatus 200taken along the line A-A of FIG. 3. The power semiconductor module 300 bis housed in the second flow path part 19 b shown in FIG. 5. The outsidewall of the module case 304 is directly brought into contact with thecooling refrigerant flowing through the second flow path part 19 b.Similarly to the power semiconductor module 300 b, the other powersemiconductor modules 300 a and 300 c as well as the power semiconductormodules 301 a to 301 c are also housed in each of the flow path parts.

The semiconductor module 300 b is provided on a side portion of thecapacitor module 500. A height 540 of the capacitor module is madesmaller than a height 360 of the power semiconductor module. Here, theheight 540 of the capacitor module is the height from a bottom portion513 of the capacitor case 502 to the capacitor terminal 503 b. Theheight 360 of the power semiconductor module is the height from thebottom portion of the module case 304 to the tip of the signal terminal325U.

Then, the second flow path forming body 442 is provided with the seventhflow path part 19 g placed below the capacitor module 500. In otherwords, the seventh flow path part 19 g is arranged side by side with thecapacitor module 500, along the height direction of the powersemiconductor module 300 b. A height 443 of the seventh flow path partis smaller than the difference between the height 360 of the powersemiconductor module and the height 540 of the capacitor module. Notethat the height 443 of the seventh flow path part may be equal to thedifference between the height 360 of the power semiconductor module andthe height 540 of the capacitor module.

As the power semiconductor module 300 b and the capacitor module 500 arearranged adjacent to each other, the connection distance is short, sothat it is possible to achieve low inductance and low loss.

Meanwhile, the power semiconductor module 300 b and the capacitor module500 can be fixed and connected on the same plane, so that it is possibleto increase the ease of assembly.

Meanwhile, as the height 540 of the capacitor module is reduced to besmaller than the height 360 of the power semiconductor module, theseventh flow path part 19 g can be provided below the capacitor module500, so that it is possible to also cool the capacitor module 500.Further, the distance between the height of the upper portion of thecapacitor module 500 and the height of the upper portion of the powersemiconductor module 300 b is short, so that it is possible to preventthe length of the capacitor terminal 503 b from increasing in the heightdirection of the capacitor module 500.

Meanwhile, by arranging the seventh flow path part 19 g below thecapacitor module 500, it is possible to avoid the cooling flow path frombeing placed on the side portion of the capacitor module 500, and tobring the capacitor module 500 and the power semiconductor module 300 bclose to each other. In this way, it is possible to prevent the wiringdistance between the capacitor module 500 and the power semiconductormodule 300 b from being increased.

Further, the driver circuit board 22 is mounted with a transformer 24 togenerate a driving power of the driver circuit. The height of thetransformer 24 is greater than the height of the circuit componentsmounted on the driver circuit board 22. The signal terminal 325U and theDC positive electrode terminal 315B are placed in the space between thedriver circuit board 22 and the power semiconductor modules 301 a to 301c. Meanwhile, the transformer 24 is placed in the space between thedriver circuit board 22 and the capacitor module 500. In this way, it ispossible to effectively use the space between the driver circuit board22 and the capacitor module 500. Further, the circuit components withthe same heights are mounted on the surface opposite the surface onwhich the driver circuit board 22 and the transformer 24 are provided.In this way, it is possible to reduce the distance between the drivercircuit board 22 and the metal base plate 11.

FIG. 13 is an exploded perspective view of the driver circuit board 22and the metal base plate 11, in which the lid 8 and the control circuitboard 20 are removed.

The driver circuit board 22 is placed above the power semiconductormodules 300 a to 300 c and the power semiconductor modules 301 a to 301c. The metal base plate 11 is provided on the opposite side of the powersemiconductor modules 300 a to 300 c and the power semiconductor modules301 a to 301 c with the driver circuit board 22 therebetween. the drivercircuit board 22 forms a through hole 22 a passing through the AC-siderelay conductor 802 a, a through hole 22 b passing through an AC-siderelay conductor 802 b, a through hole 22 c passing through the AC-siderelay conductor 802 c, a through hole 22 d passing through an AC-siderelay conductor 802 d, a through hole 22 e passing through an AC-siderelay conductor 802 e, and a through hole 22 f passing through anAC-side relay conductor 802 f, respectively. Note that in the presentembodiment, a current sensor 180 a is fitted into the through hole 22 a,a current sensor 180 c is fitted into the through hoe 22 c, a currentsensor 180 d is fitted into the through hole 22 d, and a current sensor180 f is fitted into the through hole 22 f. However, it is also possibleto provide current sensors to all the through holes 22 a to 22 f.

By providing the through holes 22 a to 22 f in the driver circuit board22, it is possible to directly provide the current sensors in the drivercircuit board 22. Thus, the wiring of the AC-side relay conductors 802 ato 802 f can be simplified, contributing to downsizing.

In the metal base plate 11, a through hole 11 a is formed at a positionfacing the through holes 22 a to 22 c, and a through hole 11 b is formedat a position facing the through holes 22 d to 22 f. Further, as shownin FIG. 3, the lid 8 forms the third opening 204 a at a position facingthe through hole 11 a to form the AC connector 188. Further, the lid 8forms the fourth opening 204 b at a position facing the through hole 11b to form the AC connector 159.

In this way, even if the driver circuit board 22 is provided between theAC connector 188 and the power semiconductor modules 301 a to 301 c, itis possible to prevent the wiring of the AC-side relay conductors 802 ato 802 f from being complicated. Thus, downsizing of the powerconversion apparatus 200 can be achieved.

Further, each of the power semiconductor modules 300 a to 300 c and 301a to 301 c has a rectangular shape with a side in the longitudinaldirection and a side in the short direction. Similarly, the capacitormodule 500 has a rectangular shape with a side in the longitudinaldirection and a side in the short direction. Then, the powersemiconductor modules 300 a to 300 c and 301 a to 301 c are arranged sothat the respective sides in the short direction are placed in a linealong the longitudinal direction of the capacitor module 500.

Because of this arrangement, the distance between the powersemiconductor modules 300 a to 300 c approaches, so that the distancebetween the capacitor terminals 503 a to 503 can be reduced. As aresult, it is possible to reduce the heat generated by the returncurrent flowing between the power semiconductor modules 300 a to 300 c .This is the same for the power semiconductor modules 301 a to 301 c.

A support member 803 of metal protrudes from the flow path forming body12 and is connected to the flow path forming body 12. The metal baseplate 11 is supported at the tip portion of the support member 803. Theflow path forming body 12 is electrically coupled to the ground. A flow804 of leakage current shows the flow direction of a leakage currentflowing from the driver circuit board 22 to the metal base plate 11, thesupport member 803, and to the flow path forming body 12, sequentially.Further, a flow 805 of leakage current shows the flow direction of aleakage current flowing from the control circuit board 20 to the metalbase plate 11, the support member 803, and to the flow path forming body12, sequentially. In this way, the leakage current of the controlcircuit board 20 and the driver circuit board 22 can flow through theground effectively.

As shown in FIG. 3, the control circuit board 20 is placed facing onesurface of the lid 8 that forms the first opening 202. Then, theconnector 21 is directly mounted on the control circuit board 20,projecting to the outside through the first opening 202 formed in thelid 8. In this way, it is possible to effectively use the space of theinterior of the power conversion apparatus 200.

Further, the control circuit board 20 on which the connector 21 ismounted is fixed to the metal base plate 11. Thus, even if a physicalforce is applied from the outside to the connector 21, the load on thecontrol circuit board 20 is reduced, so that it is expected that thereliability including durability will be increased.

FIG. 14 is a cross-sectional perspective view taken along the plane B ofFIG. 13. A connection part 23 a is the connection part of the signalterminal 325U of the power semiconductor module 301 a and the drivercircuit board 22. A connection part 23 b is the connection part of thesignal terminal 325L of the power semiconductor module 301 a and thedriver circuit board 22. The connection parts 23 a and 23 b are formedby a solder material.

The through hole 11 a of the metal base plate 11 is formed to theposition facing the connection parts 23 a and 23 b. Because of thisstructure, it is possible to perform the connection operation of theconnection parts 23 a and 23 b through the through hole 11 a of themetal base plate 11, with the driver circuit board 22 fixed to the metalbase plate 11.

Further, the control circuit board 20 is arranged in such a way thatwhen it is projected from the upper surface of the power conversionapparatus 200, the projected portion of the control circuit board 20does not overlap the projected portion of the through hole 11 a. Becauseof this arrangement, the control circuit board 20 does not interferewith the connection operation of the connection parts 23 a and 23 b. Atthe same time, the control circuit board 20 can reduce the influence ofthe electromagnetic noise from the connection parts 23 a and 23 b.

FIG. 15 is a cross-sectional view taken along the plane C of the flowpath forming body 12 shown in FIG. 5. The flow path forming body 12integrally forms the first flow path forming body 441 that forms thefirst to sixth flow path parts 19 a to 19 f, and the second flow pathforming body 442 that forms the seventh flow path part 19 g. The firstflow path forming body 441 is provided on a side portion of the secondpath forming body 442. The second flow path forming body 442 forms thehousing space 405 for housing the capacitor module 500 above the seventhflow path part 19 g. Further, the flow path forming body 12 has a wall445 for forming the side wall of the housing space 405 as well as a partof the seventh flow path part 19 g. In other words, the first to sixthflow path parts 19 a to 19 f are formed at a position facing the wall445.

In this way, not only the bottom of the capacitor module 500 is cooledby the seventh flow path part 19 g, but also the side surface in theheight direction of the capacitor module 500 is cooled by the first tosixth flow path parts 19 a to 19 f. As a result, the cooing performanceof the capacitor module 500 is improved.

Further, the wall 445 forms a part of the housing space 405, a part ofthe seventh flow path part 19 g, and a part of the fourth flow path part19 d. Because of this structure, the housing space to be cooled can bedivided by the wall 445, so that it is possible to cool down in the unitof module in each of the capacitor module and the power semiconductormodule. As a result, it is possible to select the priority of the spaceto be cooled for each housing space.

Further, the flow path forming body 12 integrally forms the first flowpath forming body 441, the second flow path forming body 442, and thethird flow path forming body 444 that forms the eighth flow path part 19h. The third flow path forming body 444 is provided on a side portion ofthe second flow path forming body 442 . The flow path forming body 12has a wall 460 for forming the side wall of the housing space 405 and apart of the eighth flow path part 19 h. In other words, the eighth flowpath part 19 h is formed at a position facing the wall 460. Because ofthis structure, not only the bottom of the capacitor module 500 iscooled by the seventh flow path part 19 h, but also the side surface inthe height direction of the capacitor module 500 is cooled by the eighthflow path part 19 h. Thus, the cooling performance of the capacitormodule 500 is further increased.

Further, the flow path forming body 12 is integrally formed with thethird flow path forming body 444 that forms the eighth flow path part 19h, in order to further simplify the structure.

Further, as shown in FIG. 12, the capacitor terminals 503 a to 503 f areformed over the upper portion of the wall 445. In this way, it ispossible to reduce the influence of the heat transferred between thecapacitor module and the power semiconductor module.

Note that, as shown in FIG. 12, an insulating member 446 is provided inan upper end of the wall 445 and is brought into contact with the relayconductor part 530 shown in FIG. 11. In this way, it is possible tofurther reduce the influence of the heat transferred between thecapacitor module and the power semiconductor module.

FIG. 16 is an upper surface view of the power conversion apparatus 200,in which the lid 8, the control circuit board 20, the metal base plate11, and the driver circuit board 22 are removed.

When the power conversion apparatus 200 is projected from the uppersurface, reference numeral 441 s indicates the projected portion of thefirst flow path forming body 441, 442 s indicates the projected portionof the second flow path forming body 442, and 444 s indicates theprojected portion of the third flow path forming body 444. The auxiliarypower module 350 is arranged so as to overlap the projected portion 444s of the third flow path forming body 444. In this way, it is possibleto cool the auxiliary power module 350 by the cooling refrigerantflowing through the eighth flow path part 19 h.

Further, the first flow path forming body 441 and the second flow pathforming body 442 are arranged facing a side wall 12 b, side wall 12 b,side wall 12 c, and side wall 12 d of the flow path forming body 12through a void portion 12 e with an air layer. In this way, even ifthere is a difference between the temperature of the cooling refrigerantflowing through the first flow path forming body 441 and the second flowpath forming body 442 and the external ambient temperature, the voidportion 12 e serves as a heat insulating layer to be able to prevent thefirst flow path forming body 441 and the second flow path forming body442 from being affected by the external ambient temperature of the powerconversion apparatus 200.

LIST OF REFERENCE SIGNS

-   8: lid-   11: metal base plate-   11 a, 11 b, 22 a to 22 f: through hole-   12: flow path forming body-   12 a to 12 d: side wall-   12 e: void portion-   13: inlet pipe-   14: outlet pipe-   19 a: first flow path part-   19 b: second flow path part-   19 c: third flow path part-   19 d: fourth flow path part-   19 e: fifth flow path part-   19 f: sixth flow path part-   19 g: seventh flow path part-   19 h: eighth flow path part-   20: control circuit board-   21: connector-   22: driver circuit board-   23 a, 23 b, 370: connection part-   24: transformer-   120, 159, 320B: AC terminal-   136: battery-   138: DC connector-   140, 142, 350B: inverter circuit-   150: upper and lower arm series circuit-   153, 163: collector electrode-   154, 164: gate electrode-   155: signal emitter electrode-   156, 166: diode-   157: positive electrode terminal-   158: negative electrode terminal-   160: metal bonding material-   165: signal emitter electrode-   168: intermediate electrode-   172: control circuit-   174, 350A: driver circuit-   180, 180 a to 180 f: current sensor-   188: AC connector-   195: auxiliary motor-   200: power conversion apparatus-   202: first opening-   203: second opening-   204 a: third opening-   204 b: fourth opening-   205: fifth opening-   300 a to 300 c, 301 a to 301 c: power semiconductor module-   302: module primary sealant-   304: module case-   304A: thin wall portion-   304B: flange-   305: fin-   306: insertion opening-   307A: first radiating surface-   307B: second radiating surface-   309: screw-   315, 318, 319, 320: conductor plate-   315A: DC positive electrode wiring-   315B: DC positive electrode terminal-   315C: auxiliary module-side DC positive electrode connection    terminal-   315D: element-side DC positive electrode connection terminal-   319A: DC negative electrode wiring-   319B: DC negative electrode terminal-   319C: auxiliary module-side DC negative electrode connection    terminal-   319D: element-side DC negative electrode connection terminal-   320A: AC wiring-   320C: auxiliary module-side AC connection terminal-   320D: element-side AC connection terminal-   322: element fixing part-   324U, 324L: signal wiring-   325L, 325U: signal terminal-   326L, 326U: auxiliary module-side signal connection terminal-   327L, 327U: element-side signal connection terminal-   328, 330: IGBT-   328A, 330A: control electrode-   329: intermediate electrode-   333, 446: insulating member-   348: first sealing resin-   350: auxiliary power module-   351: second sealing resin-   360: height of power semiconductor module-   371: bonding wire-   372: tie bar-   400 a to 400 c, 402 a to 402 c, 404: opening portion-   405: housing space-   406 a to 406 f: protruding portion-   407: cooling part-   409: seal member-   417: flow direction-   420: lower cover-   441: first flow path forming body-   441 s: projected portion of first flow path forming body-   442: second flow path forming body-   442 s: projected portion of second flow path forming body-   443: height of seventh flow path part-   444: third flow path forming body-   444 s: projected portion of third flow path forming body-   445, 460: wall-   447, 448: straight fin-   500: capacitor module-   501: laminated conductor plate-   502: capacitor case-   503 a to 503 f: capacitor terminal-   504: negative side capacitor terminal-   505: negative electrode conductor plate-   506: positive side capacitor terminal-   507: positive electrode conductor plate-   508: battery negative terminal-   509: battery positive terminal-   510: negative side power line-   511: housing part-   512: positive side power line-   513: bottom portion-   514: capacitor cell-   515 a, 515 b: noise filter capacitor cell-   516, 517: auxiliary capacitor terminal-   520 a to 520 d: hole-   530: relay conductor part-   540: height of capacitor module-   550: insulating sheet-   551: filling material-   600: auxiliary mold body-   608: wiring insulating portion-   802: AC bus bar-   802 a to 802 f: AC-side relay conductor-   803: support member-   804, 805: flow of leakage current-   DEF: differential gear-   EGN: engine-   MG1, MG2: motor generator-   TM: transmission-   TSM: power transfer mechanism

1. A power conversion apparatus comprising: a first power semiconductormodule including a power semiconductor element for converting a directcurrent to an alternating current; a capacitor module including acapacitor element for smoothing the direct current; and a flow pathforming body for forming a flow path through which a cooling refrigerantflows, wherein the flow path forming body has a first flow path formingbody that forms a first flow path part for cooling the first powersemiconductor module, and a second flow path forming body that forms asecond flow path part for cooling the capacitor module, wherein thefirst flow path forming body is provided on a side portion of the secondflow path forming body and is integrally formed with the second flowpath forming body, wherein the second flow path forming body forms ahousing space for housing the capacitor module above the second flowpath part, wherein the first flow path part is formed at a positionfacing the side wall that forms the housing space, and wherein the firstpower semiconductor module is inserted into the first flow path part. 2.The power conversion apparatus according to claim 1, wherein the sum ofthe height of the capacitor module and the height of the second flowpath part is smaller than the height of the first power semiconductormodule.
 3. The power conversion apparatus according to claim 1, whereinthe capacitor module has a capacitor-side conductor plate that isconnected to the capacitor element, and wherein the capacitor-sideconductor plate is provided between the capacitor element and the sidewall that forms the housing space.
 4. The power conversion apparatusaccording to claim 1, comprising: a driver circuit board provided in theupper portion of the first power semiconductor module; a metal baseplate provided on the opposite side of the first power semiconductormodule with the driver circuit board interposed therebetween; and anAC-side conductor protruding from the power semiconductor module to thedriver circuit board, wherein the driver circuit board forms a firstthrough hole passing through the AC-side conductor, and wherein themetal base plate forms a second through hole passing through the AC-sideterminal at a position facing the first through hole.
 5. The powerconversion apparatus according to claim 1, comprising: a driver circuitboard provided in the upper portion of the first power semiconductormodule; and a metal base plate provided on the opposite side of thefirst power semiconductor module with the driver circuit boardinterposed therebetween, wherein the driver circuit board has aconnection part of the driver circuit board and a signal terminalextending from the first power semiconductor module, and wherein themetal base plate forms a through hole at a position facing theconnection part.
 6. The power conversion apparatus according to claim 5,comprising a DC-side conductor for transferring the direct current byconnecting the first power semiconductor module and the capacitor moduleto each other, wherein the flow path forming body has a wall that formsa part of the side wall of the housing space and a part of the side wallof the first flow path part, and wherein the DC-side conductor is placedover the wall.
 7. The power conversion apparatus according to claim 6,comprising an insulation member that is provided in the space betweenthe DC-side conductor and the wall, and is brought into contact with theDC-side conductor and the wall.
 8. The power conversion apparatusaccording to claim 1, comprising a second power semiconductor module fordriving an auxiliary motor that is different from the motor driven bythe first power semiconductor module, wherein the flow path forming bodyhas a third flow path forming body that forms a third flow path part forcooing the second power semiconductor module, wherein the third flowpath part is formed in such a way that when it is projected along thearrangement direction of the capacitor module and the second flow pathpart, the shadow portion of the third flow path part does not overlapthe shadow portion of the capacitor module and the first powersemiconductor module, and wherein the second power semiconductor moduleis provided at a position facing the third flow path part.
 9. The powerconversion apparatus according to claim 1, comprising: a driver circuitboard for driving the power semiconductor element; an AC-side conductorfor transferring the alternating current; a case for housing the firstpower semiconductor module, the capacitor module, the driver circuitboard, and the AC-side conductor; and an AC connector, wherein thedriver circuit board is provided facing the power semiconductor module,wherein the AC-side connector is provided on one surface of the case soas to face the power semiconductor module with the driver circuit boardinterposed therebetween, and wherein the AC-side conductor is connectedto the AC-side connector, passing through the through hole formed in thedriver circuit board from the AC-side terminal.
 10. The power conversionapparatus according to claim 1, comprising a driver circuit board thatdrives the power semiconductor element, and is mounted with atransformer for generating a drive power of a driver circuit, whereinthe driver circuit board is provided facing the first powersemiconductor module and the capacitor module, and wherein thetransformer is provided at a position facing the capacitor module. 11.The power conversion apparatus according to claim 1, comprising a casefor housing the first power semiconductor module, the capacitor module,and the flow path forming body, wherein the case has a void portion sothat the area surrounding the capacitor module has an air layer.
 12. Thepower conversion apparatus according to claim 1, wherein the flow pathforming body has a straight fin protruding to the inside of the secondflow path.
 13. The power conversion apparatus according to claim 1 anyone of claims 1 to 12, wherein a plurality of the first powersemiconductor modules are provided, each having a rectangular shape witha side in the longitudinal direction and a side in the short direction,wherein the capacitor module has a rectangular shape with a side in thelongitudinal direction and a side in the short direction, wherein theplurality of power semiconductor modules are provided so that the sidesin the short direction of the power semiconductor modules are arrangedin a line along the side in the longitudinal direction of the capacitormodule, and wherein the flow path forming body is formed so that thefirst flow path allows the cooing refrigerant to flow between the powersemiconductor modules.
 14. The power conversion apparatus according toclaim 1, comprising: a driver circuit board for driving the powersemiconductor element; a control circuit board for outputting a controlsignal of the power semiconductor element to the driver circuit board; acase for housing the first power semiconductor module, the capacitormodule, the driver circuit board, and the control circuit board; a metalbase supported by a support member protruding from the case; and anAC-side connector facing the first power semiconductor module with themetal base interposed therebetween, wherein the metal base that holdsthe driver circuit board on the side on which the first powersemiconductor module is provided, and holds the control circuit board onthe side on which the AC-side connector is provided, and wherein thecase is electrically coupled to the ground.
 15. The power conversionapparatus according to claim 14, comprising a control-side connector fortransferring an instruction signal of a motor drive mounted on avehicle, wherein the control-side connector is provided on one surfaceof the case where the AC-side connector is provided.